Many industrial processes include liquid, semi-liquid and gas distribution systems which require automation of ball valves in the distribution pipelines of the industrial processes. Examples of such processes are food processing, chemical manufacturing and PET blow molding operations. In such processes very specific quantities of liquid product must be delivered, combined, dispensed and/or regulated in some manner by the automated ball valves so as to produce a desired final product or application. In many instances the ball valves are controlled or actuated for example by pneumatic actuators, which in turn are controlled via a computer system which controls and monitors the industrial process or application.
The actuators open, close and in general operate the ball valves to regulate the flow of product in any manner as directed by the computer system. There are many commercially available actuator systems to open and close ball valves including for example pneumatic double acting load cylinders with a rack and spur gear operating the valve stem of an attached ball valve. In such a pneumatic system, air pressure is controlled by a solenoid valve that drives the load cylinder which moves the rack and turns the spur gear which in turn rotates to the stem of the ball valve. This known arrangement allows the valve to be opened or closed in response to directed air pressure pulses.
Industry standards exist for the mounting and connection of such actuators to known ball valve designs. These standards ensure that there is some consistency across the industry, however the standards do not optimize the manufacturing and operating characteristics necessary to produce ball valves and actuators with a long lifespan. Even under the industry standards a ball valve and actuator combination may be merely a manual ball valve which has the handle removed and is bolted to the actuator so that the valve stem is fitted into a pinion in the actuator which turns the valve stem and hence the ball in the valve.
Ball valves are generally provided with a valve bonnet which houses the valve stem and is usually an integral part of the valve body. The valve bonnet extends perpendicularly upwards relative to the flow passage through the valve, and has a flange which, under the industry standards, is provided with four (4) bolt holes by which the flange is connected to the bottom of the actuator housing. The industry standards require four vertical bolts, one bolt at each corner of the flange on the bonnet which connect into threaded holes in the bottom of the actuator housing. These bolts are generally aligned in parallel with the valve stem and are subject to a significant amount of reaction torque and shear stress that occurs between the actuator and valve from internal seals and packings as well as the additive effects of forces created by fluid dynamics acting on the ball valve. Also, the axial length of the bonnet and the valve stem of the known ball valves defines a substantial distance between the actuator and the ball valve which can accentuate the torque and shear forces and so apply tremendous stress on these bolts over time.
Even before failure, any loosening of the standard valve and actuator connection due to such torque and shear forces causes misalignment between the valve stem and the rotation axis of the actuator. At the very least such a loss of centrality, or axial misalignment between the rotation axis of the valve stem and that of the actuator can place significant pressure and force on the valve seal accelerating wear and causing external leaks. In the worst case scenario, the valve stem seals can fail altogether and/or the valve body separates from the actuator. These conventional type of connections between the valve body and the actuator can survive only a certain number of cycles before failure or maintenance which of course affects not only the efficiencies and costs relating to the ball valve and actuator but which shuts down the entire process in which these devices are used.